The present invention relates to systems and methods for determining the distance between two objects or relative position of an object and, more specifically, to such systems and methods that determine distance and/or position based on the time a radio signal takes to propagate from a first location to a second location.
The present invention may be embodied as a distancing system for determining a distance between first and second locations comprising mobile and fixed units. The mobile unit is arranged at the first location and comprises first receive and first transmit portions operating at respective first and second frequencies, first and second baseband processors operating based on first and second clock signals, and a first control portion. The fixed unit is arranged at the second location and comprises second receive and transmit portions operating at the respective second and first frequencies, a third baseband processor operating based on a third clock signal, a second control portion, and a mode switch. The configuration of mode switch circuit allows communication between the fixed and mobile units or a determination of the distance between first and second locations.
The present invention may also be embodied as a method of determining a distance between first and second locations. If a plurality of fixed units are used, the present invention may further be embodied as a system or method for locating the mobile unit relative to the plurality of fixed units. In addition, the present invention may be configured as a system or method for collecting data from a plurality of locations.
These and other objects of the invention will become apparent from the following detailed discussion.